The present invention relates to an infrared suppressor device for a jet engine, and more particularly to a suppressor device which will mask the radiation from an engine exhaust so as to avoid detection by heat sensitive detector.
A power source for an aircraft generates heat which produces hot metal surfaces and also a stream of heated exhaust gas. These sources of infrared radiation, i.e., hot metal surfaces and a heated stream of exhaust gas, provide a target source for heat-seeking missiles which lock on the target source and are, thereby, led directly to the power source for the aircraft.
In providing an aircraft whose power source is not easily discernible by a heat-seeking missile, a first step would be to insulate the surfaces of the aircraft engine. The insulation of the aircraft engine surface is, however, only a first step in reducing infrared radiation from the aircraft power source. Even when the aircraft engine is well insulated, hot metal surfaces within the engine interior may still be viewed by a heat-seeking missile through an opening for exhaust gases positioned adjacent the hot interior surfaces. Thus, in addition to insulating the exterior surfaces of the engine, it is also desirable to, in some way, block the metal surfaces within the engine interior from view through the exhaust gas opening while still providing an opening for discharge of the exhaust gases.
One method for hiding hot engine parts is to provide a contoured plug which is placed in the exhaust pipe of a turbojet engine. One such device is shown and described in U.S. Pat. No. 3,693,880, entitled, "Infrared Suppressor Means", which issued to Edward F. Versaw, on Sept. 26, 1972. The plug is comprised of two half sections which are separated by a honeycomb heat shield and the aft half is air-cooled. The plug is large enough in diameter to hide from view hot engine parts forward of the plug, such as the turbine wheel, exhaust cone, flameholders, and the exhaust pipe wall.